1 정보통신공학개론 (2015 년 2 학기 ) 교과목명 ( 강의 - 실험 - 학점 ) :...

1

정보통신공학개론 (2015 년 2 학기 )

• 교과목명 ( 강의 - 실험 - 학점 ) : 정보통신공학개론 (3-0-3) • 담당교수 :  조준호 (jcho@postech.ac.kr, 054-279-2377)• 학수번호 : EECE341• 이수구분 : 전공필수 - 개설학과 :  전자 • 강의시간 /강의실 :   화 , 목 11:00~ 12:15 / LG 연구동 104 호• TA – 장태준 (taejun8@postech.ac.kr, 054-279-8017)

강의 목표 전자전기공학의 가장 중요한 분야중의 하나인 통신공학에 관한 기초적인 이론들과 그 응용방법을 포괄적으로 다룸으로써 학부수준에서 필수적인 지식을 제공한다 .

강의 선수 /수강 필수 사항 EECE233 신호 및 시스템

성적 평가 계획

Weight

1. Homework and Quiz 20 %

2. Midterm Exam (10/13 Tuesday, 11:00am-12:15pm, at LG 104)

30 %

3. Final Exam (TBA, 11:00am-12:15pm, at LG 104)

40 %

4. Participation 10 %

5. Attendance Pass/Fail

100%

2

강의 교재 A.B.Carlson, Communication systems, McGraw-Hill, 2010. (Fifth-Edition)

강의 진도 계획 1 주 : What is Communication Engineering?, Fourier analysis

2 주 : Fourier series expansion 3 주 : Fourier transform 4 주 : Stochastic processes 5 주 : Double-Sideband(DSB) amplitude modulation 6 주 : Single-Sideband(SSB) & Vestigial-Sideband (VSB) amplitude modulation 7 주 : AM demodulation, Demodulators 8 주 : Phase Modulation (PM), Frequency Modulation (FM) 9 주 : FM demodulation, Discriminators 10 주 : Phase-Locked Loop (PLL) 11 주 : Noise in communication systems 12 주 : Spread spectrum communication 13 주 : Sampling theory, Time-division multiplexing 14 주 : Pulse-Code Modulation (PCM), Differential DPCM 15 주 : Amplitude-Shift Keying(ASK),Phase-Shift Keying(PSK), Frequency-shift Keying(FSK) 16 주 : Matched filter

3

o Communication : Information transfer

통신의 정의 ? Or 목적 ?

정보의 전달

o 통신 System 의 구성 요소 (5 elements)

• Transmitter : Channel 특성에 맞도록 신호를 처리• Channel : 통신매체의 Noise, 간섭 , 과 왜곡 특성을 modeling. 예 )?

• Receiver : Transmitter 와 Channel 에 의해 변형된 신호를 복구한다 .

통신 System 의 분류 (4+2)

Tx CH Rx

4

o 통신의 장애요소• Distortion • Interference

• Noise: 피할 수 없음 ex) 열잡음

0x 0x

ix ix

5

o 통신의 장애요소• Distortion • Interference

• Noise: 피할 수 없음 ex) 열잡음

o Noise ( 잡음 ) & Bandwidth

신호대 잡음 비 정보전달 속도를 결정 주파수 대역폭

“ Fundamental Limitations ”

0x 0x

ix ix

sec]/)[1(log0

bitsWNP

WC

6

Fundamental Limitations Two constraints in designing communication system

Technological problemsFundamental physical limitations

(transmission) power(transmission) bandwidth(thermal) noise

Channel capacity of a bandlimited white Gaussian noise channel

called the Hartley-Shannon law.

sec]/)[1(log0

bitsWNP

WC

7

1.2 Modulation and Coding Modulating signal Carrier wave

Modulation vs. demodulation Modem = modulator + demodulator

8

Sinusoidal carrier waveMagnitude and phaseAmplitude and angleContinuous-Wave (CW) modulation

Amplitude Modulation (AM)Phase Modulation (PM)Frequency Modulation (FM)

Pulse modulationPulse Amplitude Modulation (PAM)Quadrature Amplitude Modulation (QAM)

9

Why modulation? For efficient transmission

Power and antenna size To overcome hardware limitations

Filter design, DC leakage, etc. To reduce noise and interference

Wideband noise reductionFM Code-Division Multiple-Access (CDMA)

For frequency assignment

10

11

For duplexing, multiplexing, and multiple-accessDuplexing

Two-way communicationFDDTDD

MultiplexingCellular Downlink (DL)Frequency-Division Multiplexing (FDM), Orthogonal FDM

(OFDM)Time-Division Multiplexing (TDM)Code-Division Multiplexing (CDM)

Multiple AccessCellular Uplink (UL) FDMA, OFDMATDMACDMA

12

Coding Methods and Benefits Coding (EECE 577 Information and Coding Theory)

Source coding = Data compressionLosslessLossy

Channel coding = Data transmissionForward Error Correction (FEC)Automatic Repeat Request (ARQ)

Source and Channel CodingsSource-channel separation theorem

It holds in some important cases.In that case, source coding and channel coding can be

performed separately.Joint source and channel coding

13

1.3 Electromagnetic Wave Propagation over Wireless Channels 1897: Marconi patents a complete wireless telegraph system.

Radio Frequency (RF) range of EM wave 3kHz (VLF)-300GHz (EHF)

Light wave of EM waveInfrared (IR)VisibleUltraviolet (UV)

기를 이용한 통신

14

Wave propagation Refraction: 굴절Diffraction: 회절Reflection: 반사

Scattering: 산란

15

Multipath phenomenonLine-of-Sight (LOS/LoS) pathNon-LOS path: delayed version

AttenuationDelay

Specular vs. diffusive Multipath fading

Deterministic vs. Random Channel ModelLTI vs. Linear Time-Varying Channel ModelsWide-sense stationary uncorrelated scattering (WSSUS)

channel model Ground-wave propagation

LOS, reflection, refractionEarth acts as a diffractor.

16

Sky-wave propagationTroposphere: 대류권 Ionosphere: 전리층Multi-hop paths

Reflection: earth Refraction: ionosphere

17

1.4 Emerging Developments Circuit switching

dedicated line, traditional telephone comm. Packet switching

shared linepacketsData transmission

Cellular Telecommunications1G 2G GSM2.5G cdmaOne3G WCDMA4G LTE: OFDM 5G, B4G: massive MIMO, mmWave, etc.

18

FDMA, TDMA Ch. 7 TDM

19

20

Code-Division Multiple-Access (CDMA: 부호분할 다중접속 ) Direct-sequence spread-spectrum modulation 2.5G cdmaOne 3G WCDMA Ch. 15

Orthogonal Frequency-Division Multiplexing (OFDM) Parallel transmission on multiple overlapping but orthogonal

sub-carriers WiMax, WiBro Some Wi-Fi 4G LTE Ch. 14

21

Wi-Fi, Bluetooth over Industrial, scientific, and medical (ISM) bandsCommercial devices need to be authorized to be sold.Use of such devices does not need authorization.Limited power transmission is allowed for experimental

devices.

Software Radio (SDR)

22

Cellular Systems and Standards:3G W-CDMA, 4G LTE

Prof. Joon Ho Cho

Department of Electrical Engineering, POSTECH

Digital Communication System: Modulation, Demodulation, & Power Spectrum

23

24

25

26

27

28

29

30

31

32

33

1.5 Social Impact and Historical Perspective

Era of Information Revolution: 정보 혁명의 시대 Era of Information Technology: 정보 기술의 시대 Era of Information and Communication Technology (ICT): 정보

통신 기술의 시대 Any time, any where, any one, any application…..

Welcome to the Exciting World of Information Age!

34

Q. 인류의 역사를 1m 자에 늘어 놓으면 ?

34

David J. Smith, 지구의 역사가 1 년이라면 - 지구와 인류의 역사를 알아가는 지식의 출발점

35

Q. 인류 역사 속의 ‘ 시대’ 들

35

1. 구석기 시대2. 신석기 시대3. 청동기 시대4. 철기 시대5. 플라스틱 시대

36

Q. 인류 역사 속의 ‘ 혁명’ 들 ?

36

1. 농업 혁명2. 상업 혁명3. 제 1 차 산업 혁명4. 제 2 차 산업 혁명 : 전기 , 화학 5. 정보통신 혁명

37

Historical Develoepemts

38

39

Q. 미래를 예측하는 가장 좋은 방법은 ?

39

미래의 특징 불확실하다